| 학회 |
한국재료학회 |
| 학술대회 |
2015년 봄 (05/14 ~ 05/15, 구미코) |
| 권호 |
21권 1호 |
| 발표분야 |
C. 에너지 재료 |
| 제목 |
Synthesis, structure, and electrochemical properties of P2-layered oxides as positive electrode materials for sodium-ion batteries |
| 초록 |
Na0.7[(Fe0.5Mn0.5)1-xCox]O2 with P2-stacking is synthesized by solid state reaction as a positive electrode material for sodium-ion batteries, and the electrochemical performance for the P2-Fe-Mn-Co system is reported. Layered P2-Na0.7[(Fe0.5Mn0.5)1-xCox]O2 with x = 0, 0.05, 0.10, and 0.20 delivers an initial capacity of ~190 mAh g-1 between 1.5 and 4.5 V vs. Na+/Na at a current of 10 mA g-1. The redox potential of Fe4+/3+ is shifted to a higher potential as Co is substituted to transition metals, while the redox potential of Mn4+/3+ shifted to a lower potential. Structural changes in the P2-Na0.7[Fe0.4Mn0.4Co0.2]O2 on desodiation/sodiation have been studied by in situ synchrotron diffraction of a capillary-based micro cell. Sodium extraction from P2 structure is occurring with a single-phase solid solution followed by a structural transition from P2 (hexagonal P63/mmc) to O2 (hexagonal P63mc) after the voltage plateau at 4.1 V, and a reversible phase transformation from O2 to P2 during subsequent sodiation process is also confirmed. The cycle stability can be enhanced by controlling voltage of the P2 material to avoid this phase transition. |
| 저자 |
Young Hwa Jung, Do Kyung Kim
|
| 소속 |
Korea Advanced Institute of Science and Technology |
| 키워드 |
layered structure; electrode materials; sodium-ion batteries; in situ XRD
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| E-Mail |
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